Tumor necrosis factor family member LIGHT acts with IL-1β and TGF-β to promote airway remodeling during rhinovirus infection

Identification of common genes of rhinovirus single/double‑stranded RNA‑induced asthma deterioration by bioinformatics analysis

Rhinovirus (RV) is the most common respiratory virus affecting humans. The majority of asthma deteriorations are triggered by RV infections. However, whether the effects of RV single- and double-stranded RNA on asthma deterioration have common target genes needs to be further studied. In the present study, two datasets (GSE51392 and GSE30326) were used to screen for common differentially expressed genes (cDEGs). The molecular function, signaling pathways, interaction networks, hub genes, key modules and regulatory molecules of cDEGs were systematically analyzed using online tools such as Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, STRING and NetworkAnalyst. Finally, the hub genes STAT1 and IFIH1 were verified in clinical samples using reverse transcription-quantitative PCR (RT-qPCR). A total of 85 cDEGs were identified. Function analysis revealed that cDEGs served an important role in the innate immune response to viruses and its regulation. Signal transducer and activator of transcription 1 (STAT1), interferon induced with helicase C domain 1 (IFIH1), interferon regulatory factor 7 (IRF7), DExD/H box helicase 58 (DDX58) and interferon-stimulating gene 15 (ISG15) were detected to be hub genes based on the protein-protein interactions and six topological algorithms. A key module involved in influenza A, the Toll-like receptor signaling pathway, was identified using Cytoscape software. The hub genes were regulated by GATA-binding factor 2 and microRNA-146a-5p. In addition, RT-qPCR indicated that the expression levels of the hub genes STAT1 and IFIH1 were low during asthma deterioration compared with post-treatment recovery samples. The present study enhanced the understanding of the mechanism of RV-induced asthma deterioration.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Rhinovirus induces airway remodeling: what are the physiological consequences?

BACKGROUND

Rhinovirus infections commonly evoke asthma exacerbations in children and adults. Recurrent asthma exacerbations are associated with injury-repair responses in the airways that collectively contribute to airway remodeling. The physiological consequences of airway remodeling can manifest as irreversible airway obstruction and diminished responsiveness to bronchodilators. Structural cells of the airway, including epithelial cells, smooth muscle, fibroblasts, myofibroblasts, and adjacent lung vascular endothelial cells represent an understudied and emerging source of cellular and extracellular soluble mediators and matrix components that contribute to airway remodeling in a rhinovirus-evoked inflammatory environment.

MAIN BODY

While mechanistic pathways associated with rhinovirus-induced airway remodeling are still not fully characterized, infected airway epithelial cells robustly produce type 2 cytokines and chemokines, as well as pro-angiogenic and fibroblast activating factors that act in a paracrine manner on neighboring airway cells to stimulate remodeling responses. Morphological transformation of structural cells in response to rhinovirus promotes remodeling phenotypes including induction of mucus hypersecretion, epithelial-to-mesenchymal transition, and fibroblast-to-myofibroblast transdifferentiation. Rhinovirus exposure elicits airway hyperresponsiveness contributing to irreversible airway obstruction. This obstruction can occur as a consequence of sub-epithelial thickening mediated by smooth muscle migration and myofibroblast activity, or through independent mechanisms mediated by modulation of the β2 agonist receptor activation and its responsiveness to bronchodilators. Differential cellular responses emerge in response to rhinovirus infection that predispose asthmatic individuals to persistent signatures of airway remodeling, including exaggerated type 2 inflammation, enhanced extracellular matrix deposition, and robust production of pro-angiogenic mediators.

CONCLUSIONS

Few therapies address symptoms of rhinovirus-induced airway remodeling, though understanding the contribution of structural cells to these processes may elucidate future translational targets to alleviate symptoms of rhinovirus-induced exacerbations.

EPs® 7630 Stimulates Tissue Repair Mechanisms and Modifies Tight Junction Protein Expression in Human Airway Epithelial Cells

Airway epithelium repair after infection consists of wound repair, re-synthesis of the extracellular matrix (ECM), and tight junction proteins. In humans, EPs^® 7630 obtained from Pelargonium sidoides roots reduces the severity and duration of acute respiratory tract infections. The effect of EPs^® 7630 on tissue repair of rhinovirus-16 (RV-16) infected and control human airway epithelial cells was assessed for: (i) epithelial cell proliferation by manual cell counts, (ii) epithelial wound repair by "scratch assay", (iii) ECM composition by Western-blotting and cell-based ELISA, and (iv) epithelial tight junction proteins by Western-blotting. EPs^® 7630 stimulated cell proliferation through cAMP, CREB, and p38 MAPK. EPs^® 7630 significantly improved wound repair. Pro-inflammatory collagen type-I expression was reduced by EPs^® 7630, while fibronectin was increased. Virus-binding tight junction proteins desmoglein2, desmocollin2, ZO-1, claudin1, and claudin4 were downregulated by EPs^® 7630. The RV16-induced shift of the ECM towards the pro-inflammatory type was prevented by EPs^® 7630. Most of the effects of EPs^® 7630 on tissue repair and regeneration were sensitive to inhibition of cAMP-induced signaling. The data suggest that EPs^® 7630-dependent modification of epithelial cell metabolism and function might underlie the faster recovery time from viral infections, as reported by others in clinical studies.

Leonotis nepetifolia Transformed Root Extract Reduces Pro-Inflammatory Cytokines and Promotes Tissue Repair In Vitro

Inflammation is closely related to asthma and its defining feature: airway remodeling. The aim of this study was to determine the effects of extracts of normal (NR) and transformed (TR) Leonotis nepetifolia roots on respiratory cells and against the gingival epithelium. Extracts from NR and TR roots were added to lung fibroblast, bronchial epithelial and gingival fibroblast cell lines, in the presence of HRV-16 infection, to determine their impact on inflammation. The expression of inflammatory cytokines (IL-6, IL-1β, GM-CSF and MCAF) as well as total thiol contents were assessed. The TR extract inhibited rhinovirus-induced IL-6 and IL-1β expression in all tested airway cells (p < 0.05). Additionally, the extract decreased GM-CSF expression in bronchial epithelial cells. The tested extracts had positive effects on total thiol content in all tested cell lines. The TR root extract demonstrated wound healing potential. While both tested extracts exhibited anti-inflammatory and antioxidative effects, they were stronger for the TR extract, possibly due to higher concentrations of beneficial metabolites such as phenols and flavonoids. Additionally, wound healing activity was demonstrated for the TR root extract. These results suggest that TR root extract may become a promising therapeutic agent in the future.

Expression of airway smooth muscle contractile proteins in children with acute interstitial pneumonia

The purpose of the present study was to investigate the expression of α-SMA and SM22α in airway smooth muscle (ASM) of bronchioles from children younger than 14 years who died of acute interstitial pneumonia (AIP). This is based upon the hypothesis that as contractile marker proteins α-SMA and SM22α can serve as an index of the overcontractile phenotype of ASM that is seen in AIP. Lung tissue samples of children were obtained from autopsies and divided into the AIP group (55.9% male and 44.1% female, between 0.4 and 132 months old, n = 34) and the control group (60% male and 40% female, between 2 and 156 months old, n = 10). We recorded the post-mortem interval (PMI), height, clinical symptoms and abdominal fat thickness (AFT) of each case. Haematoxylin-and-eosin-stained sections were used to examine the luminal area and observe the morphological changes in the bronchioles. Immunohistochemistry and Masson's trichrome staining were used to detect the expression of contractile marker proteins and the degree of pulmonary fibrosis respectively. Compared with the control group, the luminal areas of bronchioles in the AIP group were smaller (p < .001). The expression differences in α-SMA and SM22α between the two groups were statistically significant (p = .01 and p = .02 respectively). Also, there was no significant correlation of the contractile marker proteins expression with PMI, height, clinical symptoms and AFT. The collagen deposition difference in lung between the two groups was not statistically significant (p = .224). These findings suggest that enhancement of ASM contractile function appears to be involved in the death mechanism of children with AIP, which affords more insights into the understanding of AIP.

Relaxin Affects Airway Remodeling Genes Expression through Various Signal Pathways Connected with Transcription Factors

Fibrosis is one of the parameters of lung tissue remodeling in asthma. Relaxin has emerged as a natural suppressor of fibrosis, showing efficacy in the prevention of a multiple models of fibrosis. Therefore, the aim of this study was to analyze the aptitudes of relaxin, in the context of its immunomodulatory properties, in the development of airway remodeling. WI-38 and HFL1 fibroblasts, as well as epithelial cells (NHBE), were incubated with relaxin. Additionally, remodeling conditions were induced with two serotypes of rhinovirus (HRV). The expression of the genes contributing to airway remodeling were determined. Moreover, NF-κB, c-Myc, and STAT3 were knocked down to analyze the pathways involved in airway remodeling. Relaxin decreased the mRNA expression of collagen I and TGF-β and increased the expression of MMP-9 (p < 0.05). Relaxin also decreased HRV-induced expression of collagen I and α-SMA (p < 0.05). Moreover, all the analyzed transcription factors—NF-κB, c-Myc, and STAT3—have shown its influence on the pathways connected with relaxin action. Though relaxin requires further study, our results suggest that this natural compound offers great potential for inhibition of the development, or even reversing, of factors related to airway remodeling. The presented contribution of the investigated transcription factors in this process additionally increases its potential possibilities through a variety of its activity pathways.

Realigning the LIGHT signaling network to control dysregulated inflammation

Advances in understanding the physiologic functions of the tumor necrosis factor superfamily (TNFSF) of ligands, receptors, and signaling networks are providing deeper insight into pathogenesis of infectious and autoimmune diseases and cancer. LIGHT (TNFSF14) has emerged as an important modulator of critical innate and adaptive immune responses. LIGHT and its signaling receptors, herpesvirus entry mediator (TNFRSF14), and lymphotoxin β receptor, form an immune regulatory network with two co-receptors of herpesvirus entry mediator, checkpoint inhibitor B and T lymphocyte attenuator, and CD160. Deciphering the fundamental features of this network reveals new understanding to guide therapeutic development. Accumulating evidence from infectious diseases points to the dysregulation of the LIGHT network as a disease-driving mechanism in autoimmune and inflammatory reactions in barrier organs, including coronavirus disease 2019 pneumonia and inflammatory bowel diseases. Recent clinical results warrant further investigation of the LIGHT regulatory network and application of target-modifying therapeutics for disease intervention.

Neutrophils and Asthma

Although eosinophilic inflammation is characteristic of asthma pathogenesis, neutrophilic inflammation is also marked, and eosinophils and neutrophils can coexist in some cases. Based on the proportion of sputum cell differentiation, asthma is classified into eosinophilic asthma, neutrophilic asthma, neutrophilic and eosinophilic asthma, and paucigranulocytic asthma. Classification by bronchoalveolar lavage is also performed. Eosinophilic asthma accounts for most severe asthma cases, but neutrophilic asthma or a mixture of the two types can also present a severe phenotype. Biomarkers for the diagnosis of neutrophilic asthma include sputum neutrophils, blood neutrophils, chitinase-3-like protein, and hydrogen sulfide in sputum and serum. Thymic stromal lymphoprotein (TSLP)/T-helper 17 pathways, bacterial colonization/microbiome, neutrophil extracellular traps, and activation of nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 pathways are involved in the pathophysiology of neutrophilic asthma and coexistence of obesity, gastroesophageal reflux disease, and habitual cigarette smoking have been associated with its pathogenesis. Thus, targeting neutrophilic asthma is important. Smoking cessation, neutrophil-targeting treatments, and biologics have been tested as treatments for severe asthma, but most clinical studies have not focused on neutrophilic asthma. Phosphodiesterase inhibitors, anti-TSLP antibodies, azithromycin, and anti-cholinergic agents are promising drugs for neutrophilic asthma. However, clinical research targeting neutrophilic inflammation is required to elucidate the optimal treatment.

CCCTC-binding factor transcriptionally regulates Galectin-7 and activates the JNK/STAT3 axis to aggravate bronchial epithelial cell injury

OBJECTIVE

Studies have shown that the expression of CCCTC-binding factor (CTCF) is significantly upregulated in the airway epithelial cells of asthmatic patients, suggesting that CTCF may play an important role in the progression of asthma.

MATERIAL/METHODS

Human bronchial epithelial cells BEAS-2B were stimulated with transforming growth factor-β1 (TGF-β1) at a concentration of 10 ng/ml, and CTCF overexpression plasmid and CTCF small interfering RNA were transfected into the cells. The proliferation, apoptosis, inflammatory factor secretion, and airway remodeling marker protein expression of injured cells were detected. We bidirectionally regulated Galectin-7 expression in TGF-β1-induced BEAS-2B cells and overexpress CTCF, while interfering with Galectin-7 to further explore the regulatory effect of CTCF on Galectin-7. We introduced SP600125, a c-Jun N-terminal kinase c-Jun (JNK) pathway inhibitor, to investigate whether CTCF affects asthma progression through the JNK pathway.

RESULTS

The expression of CTCF in BEAS-2B cells induced by TGF-β1 was significantly upregulated, interfering with CTCF expression promoted cell proliferation, inhibited apoptosis, reduced inflammatory factors secretion, and decreased the expression of airway remodeling marker protein. Luciferase reporter gene analysis and chromatin immunoprecipitation verified that CTCF directly bound to Galectin-7 promoter. The effect of Galectin-7 on cells is consistent with the effect of CTCF on cells. The regulatory effect of CTCF on injured cells was indeed mediated by activation of the JNK/STAT3 axis.

CONCLUSIONS

CTCF transcriptionally regulated Galectin-7 and activated JNK/STAT3 axis to aggravate bronchial epithelial cell injury.

Mechanism of Rhinovirus Immunity and Asthma

The majority of asthma exacerbations in children are caused by Rhinovirus (RV), a positive sense single stranded RNA virus of the Picornavirus family. The host has developed virus defense mechanisms that are mediated by the upregulation of interferon-activated signaling. However, the virus evades the immune system by inducing immunosuppressive cytokines and surface molecules like programmed cell death protein 1 (PD-1) and its ligand (PD-L1) on immunocompetent cells. Initially, RV infects epithelial cells, which constitute a physiologic mucosal barrier. Upon virus entrance, the host cell immediately recognizes viral components like dsRNA, ssRNA, viral glycoproteins or CpG-DNA by host pattern recognition receptors (PRRs). Activation of toll like receptors (TLR) 3, 7 and 8 within the endosome and through MDA-5 and RIG-I in the cytosol leads to the production of interferon (IFN) type I and other antiviral agents. Every cell type expresses IFNAR1/IFNAR2 receptors thus allowing a generalized antiviral activity of IFN type I resulting in the inhibition of viral replication in infected cells and preventing viral spread to non-infected cells. Among immune evasion mechanisms of the virus, there is downregulation of IFN type I and its receptor as well as induction of the immunosuppressive cytokine TGF-β. TGF-β promotes viral replication and is associated with induction of the immunosuppression signature markers LAP3, IDO and PD-L1. This article reviews the recent advances on the regulation of interferon type I expression in association with RV infection in asthmatics and the immunosuppression induced by the virus.

IL-1β augments TGF-β inducing epithelial-mesenchymal transition of epithelial cells and associates with poor pulmonary function improvement in neutrophilic asthmatics

Background

Neutrophilic asthmatics (NA) have less response to inhaled corticosteroids. We aimed to find out the predictor of treatment response in NA.

Methods

Asthmatics (n = 115) and healthy controls (n = 28) underwent clinical assessment during 6-month follow-up with standardized therapy. Asthmatics were categorized by sputum differential cell count. The mRNA expressions were measured by RT-qPCR for sputum cytokines (IFN-γ, IL-1β, IL-27, FOXP3, IL-17A, and IL-5). The protein of IL-1β in sputum supernatant was detected by ELISA. Reticular basement membranes (RBM) were measured in the biopsy samples. The role and signaling pathways of IL-1β mediating the epithelial-mesenchymal transition (EMT) process were explored through A549 cells.

Results

NA had increased baseline sputum cell IL-1β expression compared to eosinophilic asthmatics (EA). After follow-up, NA had less improvement in FEV₁ compared to EA. For all asthmatics, sputum IL-1β mRNA was positively correlated with protein expression. Sputum IL-1β mRNA and protein levels were negatively correlated to FEV₁ improvement. After subgrouping, the correlation between IL-1β mRNA and FEV₁ improvement was significant in NA but not in EA. Thickness of RBM in asthmatics was greater than that of healthy controls and positively correlated with neutrophil percentage in bronchoalveolar lavage fluid. In vitro experiments, the process of IL-1β augmenting TGF-β1-induced EMT cannot be abrogated by glucocorticoid or montelukast sodium, but can be reversed by MAPK inhibitors.

Conclusions

IL-1β level in baseline sputum predicts the poor lung function improvement in NA. The potential mechanism may be related to IL-1β augmenting TGF-β1-induced steroid-resistant EMT through MAPK signaling pathways.

Trial registration: This study was approved by the Ethics Committee of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (IRB ID: 20150406).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01808-7.

Redefining the Role of Lymphotoxin Beta Receptor in the Maintenance of Lymphoid Organs and Immune Cell Homeostasis in Adulthood

Lymphotoxin beta receptor (LTβR) is a promising therapeutic target in autoimmune and infectious diseases as well as cancer. Mice with genetic inactivation of LTβR display multiple defects in development and organization of lymphoid organs, mucosal immune responses, IgA production and an autoimmune phenotype. As these defects are imprinted in embryogenesis and neonate stages, the impact of LTβR signaling in adulthood remains unclear. Here, to overcome developmental defects, we generated mice with inducible ubiquitous genetic inactivation of LTβR in adult mice (iLTβR^Δ/Δ mice) and redefined the role of LTβR signaling in organization of lymphoid organs, immune response to mucosal bacterial pathogen, IgA production and autoimmunity. In spleen, postnatal LTβR signaling is required for development of B cell follicles, follicular dendritic cells (FDCs), recruitment of neutrophils and maintenance of the marginal zone. Lymph nodes of iLTβR^Δ/Δ mice were reduced in size, lacked FDCs, and had disorganized subcapsular sinus macrophages. Peyer`s patches were smaller in size and numbers, and displayed reduced FDCs. The number of isolated lymphoid follicles in small intestine and colon were also reduced. In contrast to LTβR^-/- mice, iLTβR^Δ/Δ mice displayed normal thymus structure and did not develop signs of systemic inflammation and autoimmunity. Further, our results suggest that LTβR signaling in adulthood is required for homeostasis of neutrophils, NK, and iNKT cells, but is dispensable for the maintenance of polyclonal IgA production. However, iLTβR^Δ/Δ mice exhibited an increased sensitivity to C. rodentium infection and failed to develop pathogen-specific IgA responses. Collectively, our study uncovers new insights of LTβR signaling in adulthood for the maintenance of lymphoid organs, neutrophils, NK and iNKT cells, and IgA production in response to mucosal bacterial pathogen.

Abundant TNF-LIGHT expression in the airways of patients with asthma with persistent airflow limitation: Association with nitrative and inflammatory profiles

BACKGROUND

The role of the inflammatory secretory protein TNF-LIGHT (LIGHT) in the molecular mechanisms underlying persistent airflow limitation (PAL) in asthma remains unclear. We hypothesized that high airway LIGHT expression may be a feature of asthma with PAL associated with specific expression patterns of inflammatory molecules.

METHODS

This hypothesis was tested in 16 patients with asthma on inhaled corticosteroid treatment. Induced sputum was collected, the expression of LIGHT and 3-nitrotyrosine (NT), which reflects the footprint of reactive nitrogen species content, was measured using immunohistochemical staining, and the inflammatory molecules in the sputum supernatant were analyzed using a magnetic bead array.

RESULTS

LIGHT staining in the cells had a significantly higher intensity in participants with PAL than in participants without PAL (47.9 × 10⁴/ml vs. 5.4 × 10⁴/ml; p < 0.05). The array analysis indicated that IL-8, IL-19, matrix metalloproteinase 2, and osteopontin, were associated with high LIGHT immunoreactivity. The fractionation of 3-NT-positive cells was positively correlated with that of LIGHT-positive cells (r = 0.57, p < 0.05) and the TGF-β1 level (r = 0.61, p < 0.05). LIGHT- and 3-NT-positive cells showed significant positive correlation with the differential cell counts of neutrophils, macrophages, and eosinophils in the induced sputum. Intense immunoreactivities of LIGHT (r = -0.54, p < 0.05) and 3-NT (r = -0.42, p = 0.1) were negatively associated with decreased forced expiratory volume in 1/forced vital capacity ratio.

CONCLUSIONS

The findings suggest that LIGHT is a key component in the association between airway inflammation and airflow limitation in patients with asthma, and its expression may be persistently correlated with the abundance of inflammatory cells and inflammatory and profibrogenic radical/molecules.

Loss of regulatory capacity in Treg cells following rhinovirus infection

BACKGROUND

Respiratory infections with rhinoviruses (RV) are strongly associated with development and exacerbations of asthma, and they pose an additional health risk for subjects with allergy.

OBJECTIVE

How RV infections and chronic allergic diseases are linked and what role RV plays in the breaking of tolerance in regulatory T (Treg) cells is unknown. Therefore, this study aims to investigate the effects of RV on Treg cells.

METHODS

Treg cells were isolated from subjects with asthma and controls after experimental infection with the RV-A16 (RV16) and analyzed with next-generation sequencing. Additionally, suppression assays, quantitative PCR assays, and protein quantifications were performed with Treg cells after in vitro RV16 infection.

RESULTS

RV16 induced a strong antiviral response in Treg cells from subjects with asthma and controls, including the upregulation of IFI44L, MX1, ISG15, IRF7, and STAT1. In subjects with asthma, the inflammatory response was exaggerated and showed a dysregulated immune response compared with that in the controls. Furthermore, subjects with asthma failed to upregulate several immunosuppressive molecules such as CTLA4 and CD69, and they upregulated the inflammasome-related genes PYCARD and AIM2. Additionally, RV16 reduced the suppressive capacity of Treg cells from healthy subjects and subjects with asthma in vitro and increased T_H2 cell-type cytokine production.

CONCLUSIONS

Treg cells from healthy subjects and subjects with asthma displayed an antiviral response after RV infection and showed reduced suppressive capacity. These data suggest that Treg cell function might be altered or impaired during RV infections, which might play an important role in the association between RV and the development of asthma and asthma exacerbations.

The Role of CD40 in Allergic Rhinitis and Airway Remodelling

Background

Allergic rhinitis (AR) affects millions of people and is lack of effective treatment. CD40 is an important costimulatory molecule in immunity. However, few studies have focused on the role of CD40 in AR.

Methods

In this study, we built mouse model of chronic AR. The mice were divided into the AR, control, intravenous CD40 siRNA, and nasal CD40 siRNA groups (n = 6 each). We detected OVA-sIgE, IL-4, IL-5, IL-13, IL-10, IFN-γ, and TGF-β levels in serum and supernatant by ELISA, CD40⁺ splenic DCs, and Foxp3⁺ Tregs by flow cytometry and CD40 mRNA by RT²-PCR. We also used PAS and MT stains to assess tissue remodelling.

Results

(1) The OVA-sIgE, IL-4, IL-5, and IL-13 levels in the serum or supernatant of nasal septal membrane of AR mice were significantly higher than control. After treated with CD40 siRNA, those indicators were significantly decreased. The IFN-γ, IL-10, and TGF-β levels in AR mice were significantly lower than that in control and were increased by administration of CD40 siRNA. (2) AR mice had significantly fewer Foxp3⁺ Tregs in the spleen than control mice. After treated with CD40 siRNA, AR mice had significantly more Foxp3⁺ Tregs. (3) AR mice exhibited a significantly higher CD40 mRNA levels than control. Administration of CD40 siRNA significantly reduced the CD40 mRNA level. (4) The AR mice showed significantly greater collagen deposition than the control in MT staining. Applications of CD40 siRNA significantly reduced the collagen deposition in AR mice.

Conclusion

CD40 siRNA therapy shows promise for chronic AR as it significantly attenuated allergic symptoms and Th2-related inflammation and upregulated Foxp3⁺ Tregs. CD40 plays a role in tissue remodelling in AR, which can be inhibited by CD40 siRNA application.

Airway Remodeling Factors During Early-Life Rhinovirus Infection and the Effect of Premature Birth

Background: Early rhinovirus (RV) infection is a strong risk factor for asthma development. Airway remodeling factors play a key role in the progression of the asthmatic condition. We hypothesized that RV infection in young children elicits the secretion of growth factors implicated in airway remodeling and asthma progression. Methods: We examined the nasal airway production of remodeling factors in children ( ≤ 2 years old) hospitalized due to PCR-confirmed RV infection. Airway remodeling proteins included: MMP-1, MMP-2, MMP-7, MMP-9, MMP-10, TIMP-1, TIMP-2, EGF, Angiopoietin-2, G-CSF, BMP-9, Endoglin, Endothelin-1, Leptin, FGF-1, Follistatin, HGF, HB-EGF, PLGF, VEGF-A, VEGF-C, VEGF-D, FGF-2, TGF-β1, TGF-β2, TGF-β3, PDGF AA, PDGF BB, SPARC, Periostin, OPN, and TGF-α. Results: A total of 43 young children comprising RV cases (n = 26) and uninfected controls (n = 17) were included. Early RV infection was linked to (1) enhanced production of several remodeling factors (e.g., HGF, TGFα), (2) lower MMP-9/TIMP-2 and MMP-2/TIMP-2 ratios, and (3) increased MMP-10/TIMP-1 ratios. We also found that relative to term infants, severely premature children had reduced MMP-9/TIMP-2 ratios at baseline. Conclusion: RV infection in young children elicits the airway secretion of growth factors implicated in angiogenesis, fibrosis, and extracellular matrix deposition. Our results highlight the potential of investigating virus-induced airway remodeling growth factors during early infancy to monitor and potentially prevent chronic progression of respiratory disorders in all ages.

Increased Production of LIGHT by T Cells in Eosinophilic Esophagitis Promotes Differentiation of Esophageal Fibroblasts Toward an Inflammatory Phenotype

BACKGROUND & AIMS

Eosinophilic esophagitis (EoE) is an antigen-mediated eosinophilic disease of the esophagus that involves fibroblast activation and progression to fibrostenosis. Cytokines produced by T-helper type 2 cells and transforming growth factor beta 1 (TGFβ1) contribute to the development of EoE, but other cytokines involved in pathogenesis are unknown. We investigate the effects of tumor necrosis factor superfamily member 14 (TNFSF14, also called LIGHT) on fibroblasts in EoE.

METHODS

We analyzed publicly available esophageal CD3+ T-cell single-cell sequencing data for expression of LIGHT. Esophageal tissues were obtained from pediatric patients with EoE or control individuals and analyzed by immunostaining. Human primary esophageal fibroblasts were isolated from esophageal biopsy samples of healthy donors or patients with active EoE. Fibroblasts were cultured; incubated with TGFβ1 and/or LIGHT; and analyzed by RNA sequencing, flow cytometry, immunoblots, immunofluorescence, or reverse transcription polymerase chain reaction. Eosinophils were purified from peripheral blood of healthy donors, incubated with interleukin 5, cocultured with fibroblasts, and analyzed by immunohistochemistry.

RESULTS

LIGHT was up-regulated in the esophageal tissues from patients with EoE, compared with control individuals, and expressed by several T-cell populations, including T-helper type 2 cells. TNF receptor superfamily member 14 (TNFRSF14, also called HVEM) and lymphotoxin beta receptor are receptors for LIGHT that were expressed by fibroblasts from healthy donors or patients with active EoE. Stimulation of esophageal fibroblasts with LIGHT induced inflammatory gene transcription, whereas stimulation with TGFβ1 induced transcription of genes associated with a myofibroblast phenotype. Stimulation of fibroblasts with TGFβ1 increased expression of HVEM; subsequent stimulation with LIGHT resulted in their differentiation into cells that express markers of myofibroblasts and inflammatory chemokines and cytokines. Eosinophils tethered to esophageal fibroblasts after LIGHT stimulation via intercellular adhesion molecule-1.

CONCLUSIONS

T cells in esophageal tissues from patients with EoE express increased levels of LIGHT compared with control individuals, which induces differentiation of fibroblasts into cells with inflammatory characteristics. TGFβ1 increases fibroblast expression of HVEM, a receptor for LIGHT. LIGHT mediates interactions between esophageal fibroblasts and eosinophils via ICAM1. This pathway might be targeted for the treatment of EoE.

Macrophage GIT1 Contributes to Bone Regeneration by Regulating Inflammatory Responses in an ERK/NRF2-Dependent Way

Despite the best treatment, approximately 10% of fractures still face undesirable repair. Recently, many studies have focused on the importance of macrophages in bone repair; however, the cellular mechanisms by which they work are not yet fully understood. In this study, we explored the functions of macrophage G-protein-coupled receptor interacting protein 1 (GIT1) in healing a tibial monocortical defect model. Using GIT1^flox/flox Lyz2-Cre (GIT1 CKO) mice, we observed that a GIT1 deficiency in the macrophages led to an exacerbation of interleukin 1β (IL1β) production, more M1-like macrophage infiltration, and impaired intramembranous ossification in vivo. The results of in vitro assays further indicated that the macrophage GIT1 plays a critical role in several cellular processes in response to lipopolysaccharide (LPS), such as anti-oxidation, IL1β production alleviation, and glycolysis control. Although GIT1 has been recognized as a scaffold protein, our data clarified that GIT1-mediated extracellular-signal-regulated kinase (ERK) phosphorylation could activate nuclear factor (erythroid-derived 2)-like 2 (NRF2) in macrophages after LPS treatment. Moreover, we demonstrated that macrophage GIT1-activated ERK/NRF2 negatively regulates the 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3 (PFKFB3), facilitating the decrease of glycolysis. Our findings uncovered a previously unrecognized role of GIT1 in regulating ERK/NRF2 in macrophages to control the inflammatory response, suggesting that macrophage GIT1 could be a potential target to improve bone regeneration. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research..

The need for clean air: The way air pollution and climate change affect allergic rhinitis and asthma

Air pollution and climate change have a significant impact on human health and well-being and contribute to the onset and aggravation of allergic rhinitis and asthma among other chronic respiratory diseases. In Westernized countries, households have experienced a process of increasing insulation and individuals tend to spend most of their time indoors. These sequelae implicate a high exposure to indoor allergens (house dust mites, pets, molds, etc), tobacco smoke, and other pollutants, which have an impact on respiratory health. Outdoor air pollution derived from traffic and other human activities not only has a direct negative effect on human health but also enhances the allergenicity of some plants and contributes to global warming. Climate change modifies the availability and distribution of plant- and fungal-derived allergens and increases the frequency of extreme climate events. This review summarizes the effects of indoor air pollution, outdoor air pollution, and subsequent climate change on asthma and allergic rhinitis in children and adults and addresses the policy adjustments and lifestyle changes required to mitigate their deleterious effects.

Virus-Induced Asthma Exacerbations: SIRT1 Targeted Approach

The prevalence of asthma has increased worldwide. Asthma exacerbations triggered by upper respiratory tract viral infections remain a major clinical problem and account for hospital admissions and time lost from work. Virus-induced asthma exacerbations cause airway inflammation, resulting in worsening asthma and deterioration in the patients’ quality of life, which may require systemic corticosteroid therapy. Despite recent advances in understanding the cellular and molecular mechanisms underlying asthma exacerbations, current therapeutic modalities are inadequate for complete prevention and treatment of these episodes. The pathological role of cellular senescence, especially that involving the silent information regulator 2 homolog sirtuin (SIRT) protein family, has recently been demonstrated in stable and exacerbated chronic respiratory disease states. This review discusses the role of SIRT1 in the pathogenesis of bronchial asthma. It also discusses the role of SIRT1 in inflammatory cells that play an important role in virus-induced asthma exacerbations. Recent studies have hypothesized that SIRT1 is one of major contributors to cellular senescence. SIRT1 levels decrease in Th2 and non-Th2-related airway inflammation, indicating the role of SIRT1 in several endotypes and phenotypes of asthma. Moreover, several models have demonstrated relationships between viral infection and SIRT1. Therefore, targeting SIRT1 is a novel strategy that may be effective for treating virus-induced asthma exacerbations in the future.

Levels of the TNF-Related Cytokine LIGHT Increase in Hospitalized COVID-19 Patients with Cytokine Release Syndrome and ARDS

Many coronavirus disease 2019 (COVID-19) patients demonstrate lethal respiratory complications caused by cytokine release syndrome (CRS). Multiple cytokines have been implicated in CRS, but levels of tumor necrosis factor superfamily 14 (TNFSF14) (LIGHT) have not been previously measured in this setting. In this study, we observed significantly elevated serum LIGHT levels in hospitalized COVID-19 patients compared to healthy age- and gender-matched control patients. The assay detected bioavailable LIGHT unbound to the inhibitor Decoy receptor-3 (DcR3). Bioavailable LIGHT levels were elevated in patients both on and off ventilatory support, with a trend toward higher levels in patients requiring mechanical ventilation. In hospitalized patients over the age of 60, who exhibited a mortality rate of 82%, LIGHT levels were significantly higher (P = 0.0209) in those who died than in survivors. As previously reported, interleukin 6 (IL-6) levels were also elevated in these patients, with significantly (P = 0.0076) higher levels observed in patients who died than in survivors, paralleling the LIGHT levels. Although attempts to block IL-6 binding to its receptor have shown limited success in COVID-19 CRS, neutralization of LIGHT may prove to be more effective owing to its more central role in regulating antiviral immune responses. The findings presented here demonstrate that LIGHT is a cytokine which may play an important role in COVID-19 patients presenting with acute respiratory distress syndrome (ARDS) and CRS and suggest that LIGHT neutralization may be beneficial to COVID-19 patients.

Type 2 immunity in the skin and lungs

There has been extensive progress in understanding the cellular and molecular mechanisms of inflammation and immune regulation in allergic diseases of the skin and lungs during the last few years. Asthma and atopic dermatitis (AD) are typical diseases of type 2 immune responses. interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin are essential cytokines of epithelial cells that are activated by allergens, pollutants, viruses, bacteria, and toxins that derive type 2 responses. Th2 cells and innate lymphoid cells (ILC) produce and secrete type 2 cytokines such as IL-4, IL-5, IL-9, and IL-13. IL-4 and IL-13 activate B cells to class-switch to IgE and also play a role in T-cell and eosinophil migration to allergic inflammatory tissues. IL-13 contributes to maturation, activation, nitric oxide production and differentiation of epithelia, production of mucus as well as smooth muscle contraction, and extracellular matrix generation. IL-4 and IL-13 open tight junction barrier and cause barrier leakiness in the skin and lungs. IL-5 acts on activation, recruitment, and survival of eosinophils. IL-9 contributes to general allergic phenotype by enhancing all of the aspects, such as IgE and eosinophilia. Type 2 ILC contribute to inflammation in AD and asthma by enhancing the activity of Th2 cells, eosinophils, and their cytokines. Currently, five biologics are licensed to suppress type 2 inflammation via IgE, IL-5 and its receptor, and IL-4 receptor alpha. Some patients with severe atopic disease have little evidence of type 2 hyperactivity and do not respond to biologics which target this pathway. Studies in responder and nonresponder patients demonstrate the complexity of these diseases. In addition, primary immune deficiency diseases related to T-cell maturation, regulatory T-cell development, and T-cell signaling, such as Omenn syndrome, severe combined immune deficiencies, immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, and DOCK8, STAT3, and CARD11 deficiencies, help in our understanding of the importance and redundancy of various type 2 immune components. The present review aims to highlight recent advances in type 2 immunity and discuss the cellular sources, targets, and roles of type 2 mechanisms in asthma and AD.

Novel findings in immunopathophysiology of chronic rhinosinusitis and their role in a model of precision medicine

Our understanding of the pathophysiology of chronic rhinosinusitis (CRS) is continuously evolving. The traditional description of CRS in terms of two phenotypes based on the presence or absence of nasal polyps belies the underlying intricate immunopathophysiological processes responsible for this condition. CRS is being increasingly recognized as a disease spectrum encompassing a range of inflammatory states in the sinonasal cavity, with non-type 2 inflammatory disease on one end, type 2 inflammatory, eosinophil-heavy disease on the other and an overlap of both in different proportions in between. Abundance in research on the immune mechanisms of CRS has revealed various new endotypes that hold promise as biomarkers for the development of targeted therapies in severe, uncontrolled CRS. The introduction of precision medicine to manage this chronic, complex condition is a step forward in providing individualized care for all patients with CRS. In this review, the latest research on the pathophysiology of CRS with a focus on potential novel biomarkers and treatment options over the last 2 years are summarized and integrated into a suggested model of precision medicine in CRS.

Immunologic and Non-Immunologic Mechanisms Leading to Airway Remodeling in Asthma

Asthma increases worldwide without any definite reason and patient numbers double every 10 years. Drugs used for asthma therapy relax the muscles and reduce inflammation, but none of them inhibited airway wall remodeling in clinical studies. Airway wall remodeling can either be induced through pro-inflammatory cytokines released by immune cells, or direct binding of IgE to smooth muscle cells, or non-immunological stimuli. Increasing evidence suggests that airway wall remodeling is initiated early in life by epigenetic events that lead to cell type specific pathologies, and modulate the interaction between epithelial and sub-epithelial cells. Animal models are only available for remodeling in allergic asthma, but none for non-allergic asthma. In human asthma, the mechanisms leading to airway wall remodeling are not well understood. In order to improve the understanding of this asthma pathology, the definition of “remodeling” needs to be better specified as it summarizes a wide range of tissue structural changes. Second, it needs to be assessed if specific remodeling patterns occur in specific asthma pheno- or endo-types. Third, the interaction of the immune cells with tissue forming cells needs to be assessed in both directions; e.g., do immune cells always stimulate tissue cells or are inflamed tissue cells calling immune cells to the rescue? This review aims to provide an overview on immunologic and non-immunologic mechanisms controlling airway wall remodeling in asthma.

Bu-Shen-Yi-Qi formula ameliorates airway remodeling in murine chronic asthma by modulating airway inflammation and oxidative stress in the lung

Bu-Shen-Yi-Qi formula (BSYQF) could suppress chronic airway inflammation according to previous studies. However, there is relatively little direct experimental evidence to evaluate the effects of BSYQF treatment on airway remodeling in chronic asthma. Recent evidence suggests that oxidative stress is involved in airway inflammation and airway remodeling in chronic asthma. BSYQF which includes various of chemical components having antioxidant effects, could be beneficial in attenuating airway remodeling in chronic asthma. The purpose of this study was to elucidate the effect of BSYQF treatment on airway remodeling and investigate its potential mechanisms in chronic asthma. To develop the murine models of chronic asthma, BALB/c mice were sensitized and challenged to ovalbumin for 8 weeks. BSYQF (5, 10, 20 g raw herbs/kg body weight) or tiotropium bromide (0.1 mM) were administered orally and intranasal instillation, respectively. The effect of BSYQF on pulmonary inflammation and remodeling was evaluated. The parameters of oxidative stress in the lung were analyzed. BSYQF treatment reduced airway hyperresponsiveness (AHR), Th2 response including IL-4, IL-13, and OVA-specific IgE and IgG1, transforming growth factor-β (TGF-β), vascular endothelium growth factor (VEGF), airway inflammation and airway remodeling including smooth muscle thickening and peribronchial collagen deposition. As for oxidative stress, BSYQF treatment reduced reactive oxygen species (ROS), Malondialdehyde (MDA), NO, and the expression of inducible nitric oxide synthase (iNOS), but increased significantly glutathione (GSH) /Oxidized glutathione(GSSH) ratios in the lung, restored mitochondrial ultrastructural changes of bronchial epithelia and ATP levels in the lung. In summary, this study suggested that BSYQF treatment ameliorated airway remodeling and alleviated asthmatic features in chronic asthma models. Anti-inflammatory and antioxidant effect of BSYQF may explain why BSYQF has effects on preventing airway remodeling.

Neonatal Streptococcus pneumoniae Pneumonia Induces an Aberrant Airway Smooth Muscle Phenotype and AHR in Mice Model

Our previous study showed that neonatal S. pneumoniae infection aggravated airway inflammation and airway hyperresponsiveness (AHR) in an OVA-induced allergic asthma model. As airway smooth muscle (ASM) plays a pivotal role in AHR development, we aim to investigate the effects of neonatal S. pneumoniae pneumonia on ASM structure and AHR development. Non-lethal neonatal pneumonia was established by intranasally infecting 1-week-old BALB/C mice with the S. pneumoniae strain D39. Five weeks after infection, the lungs were collected to assess the levels of α-SMA and the contractile proteins of ASM. Our results indicate that neonatal S. pneumoniae pneumonia significantly increased adulthood lung α-SMA and SMMHC proteins production and aggravated airway inflammatory cells infiltration and cytokines release. In addition, the neonatal S. pneumoniae pneumonia group had significantly higher Penh values compared to the uninfected controls. These data suggest that neonatal S. pneumoniae pneumonia promoted an aberrant ASM phenotype and AHR development in mice model.

Elevated expression of microRNA-378 in children with asthma aggravates airway remodeling by promoting the proliferation and apoptosis resistance of airway smooth muscle cells

The present study determined the expression of microRNA (miR)-378 in the peripheral blood and lung tissues of children with asthma, and investigated its effect and mechanism of action on the biological functions of airway smooth muscle cells. A total of 23 asthmatic children and 15 healthy children were included in the study. Peripheral blood and tissues were obtained from asthmatic children. Healthy children provided peripheral blood. Quantitative real-time polymerase chain reaction was used to determine the expression of miR-378. Airway smooth muscle cells were isolated and cultured in vitro. The cells were transfected with miR-378 mimics or miR-378 inhibitor. Following transfection, proliferation of the cells was determined using the CCK-8 assay. In addition, flow cytometry was used to detect the cell cycles and apoptosis of smooth muscle cells. Western blotting was performed to determine the expression of extracellular matrix proteins in smooth muscle cells. Furthermore, bioinformatics was used to predict potential target genes of miR-378 and their downstream signaling pathways. Results indicated that the expression of miR-378 in peripheral blood and lung tissues from asthmatic children was increased compared with that in healthy children. Serum from asthmatic children promoted the proliferation of smooth muscle cells in vitro by affecting the cell cycle, and enhanced apoptotic resistance of smooth muscle cells. Notably, overexpression of miR-378 increased the proliferation of smooth muscle cells by affecting the cell cycle, and this upregulated apoptotic resistance of smooth muscle cells and enhanced the expression of extracellular matrix-related proteins in smooth muscle cells. However, downregulation of miR-378 expression reversed the promoting effect of serum from asthmatic children on the biological functions of smooth muscle cells. These findings suggested that miR-378 possibly affects the proliferation, apoptosis and motility of airway smooth muscle cells via downstream signaling pathways. To conclude, the present study demonstrated that miR-378 expression was elevated in the peripheral blood and lung tissues from children with asthma. Furthermore, miR-378 promoted the biological functions of extracellular matrix-related proteins of smooth muscle cells, and possibly exerts its effect via its target genes through downstream signaling pathways.